In this disclosure, the term “pattern recognition” refers to the detection, estimation and classification of entities useful for performing a task. These entities may include high-level task-dependent objects such as roads, cars and faces; generic low-level features, such as edges; and any other auxiliary or intermediate entity that may be useful for recognizing a more complex object, such as an object part or a combination of low level features. Some examples of existing pattern recognition and edge detection inventions are disclosed in European Patents 1,488,410 and 1,394,727; U.S. Pat. No. 6,690,842; and WO 2005/010803. While the exemplary embodiments described in this disclosure relate mostly to the recognition of edge features in images, those skilled in the art will appreciate how the disclosed invention can be utilized to recognize other types of features and objects. If a pattern recognition method relies on a model of the entity of interest, which is the most common situation, then the term “model recognition” is also used, with intended meaning comprising “pattern recognition” and “feature extraction”.